小波变换在薄层地震信号分析中的应用

Wavelet Transform Analysis of Thin-Bed Seismic Signal

基于小波变换的多分辨率特性和调焦作用 ,提出了利用小波在薄层地震记录上检测其结构特性和估算薄层厚度的新方法 .采用“接近零相位子波”的小波函数作为基本小波 ,通过分频扫描可以以较高的分辨率检测出薄层的结构 ,并可直接根据各分频剖面振幅或者振幅包络的变化 ,确定调谐振幅和频率 ,从而估算出薄层的厚度 .与常规的振幅 时间厚度交会图解方法相比 ,新方法不需要制作量板 ,具有较强的抗干扰能力 ,厚度估计误差较小 ,更能反映薄地层厚度变化的真实情况 .经仿真实验验证 ,新方法是有效的 .

Multi resolution and focusing of wavelet transform are applied to examine thin bed texture whereby its thickness is registered on the seismic record. Close to a zero phase wavelet is used. It has higher resolution for detecting the thin bed texture through frequency division scanning. The new method can determine the tuning amplitude and frequency directly in terms of the amplitude changes or amplitude envelope in the frequency division sections. This provides an estimate of the thickness. Compared with the routine graphic solution of amplitude and time thickness, the new aprroach has the ability to resist to noise. Moreover, the thickness estimate error is smaller. The obtained results are more consistent with the actual changes of the thin bed thickness.